Don Terrill’s Speed-Talk

And with the magic of software, now those hexadecimal numbers are easier to deal with.

I think that is exactly the same or very close to the 1995 G30 factory spark table in tuner pro.

If it were me and I was going to be towing in Northern Oregon on steeper grades, I would be looking around for a mid 90's-2000 3/4 ton truck or van with a big block and a 4L80 tranny and 4:11 gears. When it comes to towing weight there really is "No replacement for Displacement" and the 500ft/lbs that can easily be extracted from a slightly worked over 7.4L 454 is never going to be equaled by the small block ! "Right Tool for the Right Job"! Just my years of towing and engine building expertise. Tune till your hearts delight but torque is for towing, go big!

I agree, but the ramjet cam only cost me $85 and the other items needed to switch to the roller cam, if the block is compatible are inexpensive. I am checking the ads for a clean low miles big block rig in my price range. Until then I don't see the harm in trying, and its a learning tool too. The vans I find usually have very high miles and are beat. To go south on I-5, I have the Siskiyou Summit, that equals about 30 minutes of constant torture for the engine, then the brake test on the other side - even semis are running on the curb with the flashers going. North is a little easier but not much.

Hi Don,
The file I posted was a '94 and I would imagine a '95 would be very similar. Your tunerpro looks good and i have heard good things about it, just no experience with it.
What was the broadcast code of the chip you started with? Did you modify the DRAC module to correct the speedometer stuff? If the mph isn't correct the shifting will be messed up.
Just advice, carry on.

The VSSB is correct. I got one from a 95 suburban with the correct gear and tire size for a dollar off eBay. I think what you are asking for is $0D. Thats what tunerpro wants its files to be to read the bin in my van correctly.

Newold1 wrote: ↑Thu Jun 07, 2018 7:57 pm If it were me and I was going to be towing in Northern Oregon on steeper grades, I would be looking around for a mid 90's-2000 3/4 ton truck or van with a big block and a 4L80 tranny and 4:11 gears. When it comes to towing weight there really is "No replacement for Displacement" and the 500ft/lbs that can easily be extracted from a slightly worked over 7.4L 454 is never going to be equaled by the small block ! "Right Tool for the Right Job"! Just my years of towing and engine building expertise. Tune till your hearts delight but torque is for towing, go big!

I've never seen A 88-98 3/4 ton with a big block....Were they available in that series?

Awesome find on the vss drac module, OD is the program id code located at 4008, OD was used on most 94-95 4.3 and 350 4L60E eproms, OE was used on the 4L80E stuff. The 4 digit broadcast code would have been on the silverish sticker of the original eprom and also usually on the blue memcal cover as well as the white sticker on the ecu itself. example, '95 350 4L60E with 3.73 gears would be a BJYA or BJYB from memory.

00004000 0113 FFFF FFFF 7C59 OD01 E10C 97A5 0018 ......|Y........

I'm just curious what your broadcast code was as I don't remember seeing one with a 3.23 gear, not too many hot rod vans that needed chip work back in the day.

Man, I don't do much eprom work anymore, lol.

Truckedup wrote: ↑Thu Jun 07, 2018 9:04 pm I've never seen A 88-98 3/4 ton with a big block....Were they available in that series?

I like this site. Its an old sales info page for GM. I downloaded the copies for my vehicles. I have seen C2500 trucks with 454. There was an ad for one a few days ago I considered, but the owner started talking about a radiator problem and I did not want to drive that far to find trouble.
https://www.gmheritagecenter.com/gm-her ... -kits.html

My ecm is 2-3 generations earlier than yours. I started with the hex image from the stock chip, printed formula and definition tables a friend gave me, a calculator, and a hex editor in the mid 90's, then as various freeware programs became available I went from promdata to winbin to tunerpro. I had to make my own definition file, it's not complete but does all the data I need to worry about. Other people have put definition files for my chip online now, but I just stay with mine. Your chip, the 27SF512, is a flash chip that is already electrically eraseable so no clunky 20 minute UV erase step before burning a new image like mine - lucky you. That's why I made the little adapter to step up to a chip like yours. Good luck with your tuning.

Mines a 1989 5.7L, I found two big block radiators for the GMT400- so they were available.

Before I would buy another vehicle which you also would have labor in pulling that motor out also. I would take your 350 out and make it a 383. you might have way less money invested doing it this way also. Plus you could build it to your liking. My van has a 305 in it I have never pulled anything with it-I no better

donforeman wrote: ↑Thu Jun 07, 2018 9:42 pm

Truckedup wrote: ↑Thu Jun 07, 2018 9:04 pm I've never seen A 88-98 3/4 ton with a big block....Were they available in that series?

I like this site. Its an old sales info page for GM. I downloaded the copies for my vehicles. I have seen C2500 trucks with 454. There was an ad for one a few days ago I considered, but the owner started talking about a radiator problem and I did not want to drive that far to find trouble.
https://www.gmheritagecenter.com/gm-her ... -kits.html

Uhhh, I still think the 454 was not available in a 1/2 or 3/4 ton for 88-98 , just the one ton series like a dually...

Truckedup wrote: ↑Fri Jun 08, 2018 6:54 am Uhhh, I still think the 454 was not available in a 1/2 or 3/4 ton for 88-98 , just the one ton series like a dually...

https://www.gmheritagecenter.com/docs/g ... -Truck.pdf
Page 37 C/K2500HD with L19 Option
On page 6 it does say that only an estimated 5% of the 2500 production run are made with this option, vs 25% with the 3500.

https://www.gmheritagecenter.com/docs/g ... -Truck.pdf
Page 37 C/K2500HD with L29 option

Truckedup wrote: ↑Fri Jun 08, 2018 6:54 am

donforeman wrote: ↑Thu Jun 07, 2018 9:42 pm

Truckedup wrote: ↑Thu Jun 07, 2018 9:04 pm I've never seen A 88-98 3/4 ton with a big block....Were they available in that series?

I like this site. Its an old sales info page for GM. I downloaded the copies for my vehicles. I have seen C2500 trucks with 454. There was an ad for one a few days ago I considered, but the owner started talking about a radiator problem and I did not want to drive that far to find trouble.
https://www.gmheritagecenter.com/gm-her ... -kits.html

Uhhh, I still think the 454 was not available in a 1/2 or 3/4 ton for 88-98 , just the one ton series like a dually...

Not a truck per se, but I owned a 88 (or 89) Suburban 3/4 ton 2WD with the 454/T400. I regret selling it.